by Paul Bertorelli
If the generally accepted wisdom that engine development drives aircraft development is true, is the reverse also true? Does the lack of cutting-edge propulsion stunt the industry? Who can say? All we know for sure is that we havent seen any cutting-edge engines lately but we definitely have a stunted industry.
Catching us by surprise-and obviously hoping to change that calculus-comes Bombardier/Rotax, a Canadian conglomerate with no small amount of experience in the engine world, but not much in the field of certified aircraft engines. In late April, we began to hear rumors that Bombardier was up to something big but none of this was confirmed until May when the company announced that indeed it would introduce new certified piston engines at EAAs Oshkosh AirVenture show in July.
But what exactly do they have in mind? The company is being extraordinarily secretive about its plans, leading us to wonder if this is just another aviation trial balloon. In mid-May, we were invited to an advance press conference unveiling Bombardiers plans, but only if we would sign a non-disclosure contract agreeing not to reveal the details until July. But wheres the fun in that? A Bombardier spokesman allowed as how this sort of thing is done all the time but not in our world. Accordingly, weve put together what we believe is a fair overall picture of what Bombardier will attempt later this year. (We don’t yet know what the companys time frame for introduction is.)
Two Engines
Based on interviews with sources familiar with development at Bombardiers Rotax plant in Gunskirchen, Austria, where most of its engine production and R and D happens, we believe Bombardier will initially introduce two new certified powerplants, the V220 and V300T. We believe these will appear under the Bombardier name, not the Rotax nameplate. (More on that later.)
As the nomenclature suggests, these are probably both V designs, one normally aspirated and one turbocharged. We havent confirmed the horsepower ranges yet but given the market stratification, any manufacturer serious about taking on Lycoming and Continental will need engines in the 200- and near 300-HP range. Our guess is thats the power these engines will have.
Whats special about them? V-designs are essentially unknown for modern certified aircraft, so are overhead cams and liquid cooling, which the engines reportedly have. Were told that they are also reduction geared designs, which would be in keeping with Rotaxs experience in its other aviation engines.
FADEC of some kind is almost a certainty and that suggests fuel injection rather than the carbureted designs found in the Rotax-powered Diamond Katana A1. We cant imagine how any successful new engine will have carburetion since making it as efficient as fuel injection isn’t technically feasible. (Then again, efficiency has never been a priority of engine manufacturers; theyve been happy to solve cooling issues by throwing increasingly expensive gasoline at the problem.)
To us, the proposed engines sound suspiciously like the Rotax 936, a developmental engine the company had in the works some five years ago, when Diamond was still new in the Katana market and fishing for new engines for follow-on products.
Who Are These Guys?
So much for the plans, as theyve been described to us. Does Bombardier have the technical smarts and market savvy to pull this off? we’ll know in a couple of years but it shouldnt lack for technical resources and capital.
Rotax is a division of Canadian conglomerate Bombardier, which has extensive holdings in the transportation business, including aerospace. Its divisions build the Lear and Challenger bizjets and market these into the Flexjet fractional ownership program.
On the piston-engine side, Bombardier owns Evinrude and Johnson, the outboard motor makers and the Rotax engine division makes motors for ultralights, carts, scooters, snowmobiles, watercraft and all-terrain vehicles. (The parent company takes its name from Joseph A. Bombardier, who invented the snowmobile upon which the company founded its business.)
Bombardier recently announced that it will sell off its recreational division, which includes Rotax and with it, presumably, goes the small-engine business. Were told that a new unit will be formed to build and market aircraft engines. It will probably carry the Bombardier name but the company refuses to confirm this.
Rotax has developed a specialty of high output from small, relatively light engine blocks. Its marine engines are two-cylinder designs, also two stroke. Thats true of its specialized cart engines as well. The company seems to have little or no experience with large horsepower aircraft engines.
In that context, the V220 and V300T represent design departures for Bombardier in a field where many have stumbled before, not the least of which are Continental and Lycoming.
Diamonds Experience
In the world of certified airplanes in the U.S., the only way to judge Bombardier is by its service history with Diamonds Katana A1, which was introduced in North America in 1994. The A1 has a Rotax 912F, a sophisticated engine-at least by aircraft standards-that delivers an impressive 80 HP from only 73.9 cubic inches, a better than one-to-one displacement-to-power ratio. Nothing Lycoming or Continental make comes close to that.
Rotax achieved this by relatively high RPM; the 5800 RPM at the crankshaft is geared down to 2550 at the prop, which is a constant speed Hoffman design for the Katana. However, what the gears giveth in shaft reduction, they taketh away in efficiency. With the inherent friction of that high RPM and gearing load, fuel specifics for the Rotax arent exactly spectacular. Even though it sips fuel at the miserly rate of 4.3 GPH, typically, its brake specific fuel consumption is in the .43 pounds per horsepower range.
In the aggregate, that doesnt matter much for a little airplane. But scale it up and a 200 HP engine will suck down 15 gallons an hour and in the typical airframe we imagine such an engine would be suited for, thats a hard hit against range and endurance, not to mention marketability against emerging aerodiesels with promised fuel efficiency in the .33 to .35 BSFC range. Even existing designs from Continental can hit the low .40s and high .30s.
Like individuals, industrial organisms tend to follow the path of least resistance and go with what theyre comfortable with. If that turns out to be a high-RPM geared engine of some sort, Bombardier will have to resort to some tricks with the ignition and fuel systems to keep their new powerplants competitive with existing technology, let alone the new diesels. In the end, a geared engine might not be able to deliver this kind of efficiency, period.
On that count, the 912F and the later, higher-output S-model, were so-so. Rather than fuel injection, they had carburetors and both models sported automotive-type CDI ignition systems powered by a dedicated alternator system built into the flywheel. (In the Katana, the airplane electrical system had its own external alternator system.)
No mixture control, either. Leaning in the Rotax engines is via altitude-compensating carburetion with minimal variable timing. Any owner of a BMW motorcycle would instantly recognize the Bing sidedraft carburetors used in the Rotax.
The sum of this design philosophy is to give up efficiency in the name of operational if not maintenance simplicity. We don’t know if Bombardier will adhere to this design philosophy in its new engines. We hope not, however.
One feature unique to the Rotax 912 design was its use of water-jacketed cooling for the cylinder heads with conventional air cooling for the cylinders, the idea being that most of the heat and the problems associated with it are likely to impact the top end of the engine, specifically the valves.
At the expense of some plumbing, a water pump and a small radiator, water cooling introduces a degree of thermal stability that a straight air-cooled engine cant match. On the other hand, dual cooling means you have to both run plumbing and get the baffling right. If you believe in shock cooling, water cooling can make that demon go away. And even if it doesnt, thermal stability is much vaunted as a means of reducing engine wear and improving longevity. (This is a selling point of FADECs for existing engines.) Did the water cooling work? We havent heard many complaints of cylinder cracking in Katanas nor any dings against the idea of water cooling. The Rotax cooling system is simple and apparently not a maintenance hog nor prone to leaks. You do need to check the anti-freeze, however.
In general, the 912 series engines get good to mixed reviews from the field, which is to say operators found them neither outstanding nor terrible. One chronic complaint for mechanics accustomed to, say, a Lycoming O-320, is maintenance complexity. Any mechanic with a ballpeen hammer, a drift and a pair of channel locks can fix a Lycoming. You need some schooling to fix a Bing carb.
No Follow Up
If the Rotax 912 series was so great or at least not that bad, why isn’t it still used in current Katana production? Several reasons. The original version, the 912F, was too underpowered for the airframe, delivering weak climb performance in high density altitude conditions, a shortcoming that may not have damaged Katana sales but didnt help, either.
Second, as Diamond inevitably looked for ways to both improve the Katana and introduce follow-on products-these eventually became the Evolution, the Eclipse and the four-place Star-it logically looked to Rotax for powerplants for these products.
At the time-about 1999- Diamond told us that Rotax was simply slow on the developmental uptake, forcing Diamond to look to-you guessed it, Continental and Lycoming. For its follow-on Katana, the C1/Evolution/Eclipse, Diamond used Continentals IO-240 and for the Star, the Lycoming 180-HP IO-360-M1A, both low-tech engines.
Another aspect of the Rotax 912 is that its overhaul costs proved to be somewhat of a disappointment. When it was initially marketed, Diamond expected the overhaul price for a Rotax to be about $6000, including propeller, for exchange; ship the old engine back to Rotax, bolt on a new engine and fly away the next day.
In reality, Rotax overhaul costs have escalated, probably due to low volume and/or other unforeseen developments. Initially, the 912F had a 1000-hour TBO and a proposed overhaul cost of $6000. The TBO was recently raised to 1500 hours but the overhaul cost has risen to $11,000, plus prop. And there’s no exchange option.
Unfortunately for Rotax, that may be too little, too late, as was its introduction of the more powerful 912S for the Katana. On a per-hour basis to TBO, the Rotax engine reserve works out to $7.30 an hour, plus prop. An O-235 Lycoming in a Cessna 152 overhauls for $13,000 and the Continental O-200 in the Cessna 150 for under $12,000. The Lycoming has up to a 2400-hour TBO , the Continental 1800 hours for hourly costs ranging from $5 to $7.
Moreover, both the Lyc and Continental engines suffer the travails of the training world gracefully, which means operators slap used cylinders on them, nurse the mags and other parts along for hours and depend on inexperienced mechanics to keep them running. The Rotax is more finicky; its not an engine for shade-tree maintenance.
Bottom lining it here, Rotax produced a certified engine that delivered less power than its competition, had not-so-great fuel specifics and required more sophisticated maintenance than the average shop could muster, all at a cost slightly greater than what was already available, on a per-hour basis. Its promised follow-up products were too far over the horizon for anyone to see.
If that doesnt sound like a recipe for success, it wasnt. Continental snapped up the Diamond business with the IO-240, which is itself a competent but not exceptional engine, in our estimation. Few current production airplanes use Rotax engines, although many experimentals do.
Tall Order
Bombardiers chances of success with these new engines doesnt quite sink to the fat-chance level, but they face a daunting challenge. The market has never been kind to new engine ideas and its harsher than ever now.
With only a bright spot here and there, piston-engine production in the U.S. is again declaring itself to be a sunset industry. Volumes are low, margins are slim and by dint of the certification straightjacket, the two major players-Continental and Lycoming-have a stranglehold on the market.
To suffer the expense of certifying a new engine in an existing airframe, there needs to be a payoff for both the engine maker and the airframer and thats usually a lasting relationship with at least modest volume. (Rotax didnt manage to hit that stride with Diamond.)
That successful relationship depends, to a large extent, on a reasonably good service history and unwavering support for the product. Again, Rotax didnt wow us in this regard.
On the plus side, where we would be without bright, optimistic MBAs with fantasy world business plans that venture where the experienced fear to tread? There could be an opportunity here and perhaps Bombardier is we’ll positioned to seize it.
First, on the service and support front, there’s rising disgust with Continental and Lycoming, especially following the recent crankshaft recall fiascos by both companies. Lycomings recall, although handled as we’ll as might be expected, damaged the industry, in our view, and left many customers looking for a better mousetrap. Or any mousetrap.
A reader of our sister publication, AVweb.com, volunteered his Mooney 201 as a testbed airplane for Bombardier and he has one of the good Lycoming engines.
Second, the timing could be interesting. The aircraft industry has traditionally been cyclic and if were not at the bottom of a cycle now, you can surely see the bottom from here. With the right products, Bombardier might launch into the rising arc of the next upswing. That could be perfect timing. And just because no one else has homered with a new aircraft engine-including Bombardier/Rotax itself-it doesnt mean they cant.
But we think to succeed, Bombardier will have to get everything mostly right. Heres our short list:
• No also-ran engines. If the new powerplants are the equivalent of products from Lycoming and Continental, why bother?
• Pay attention to fuel specifics. With diesels on the way, .43 to .45 wont be impressive. We think the days of the market tolerating gas guzzling aero engines are coming to an end.
• Lets see some practical, forward-thinking engineering, not overly complex designs that are difficult to manufacture and even more difficult to repair.
• Promise and deliver on dispatch and flight reliability. Conduct realistic testing before going to market so customers wont be flying Beta engines over the Sierras at night.
• If Bubbas Engine Emporium cant fix Bombardier engines, provide a service and support network that can.
• don’t expect to succeed with conditional or introductory TBOs that are substantially below 2000 hours.
• don’t hang the airframers out to dry in figuring out fuel, cooling and installation problems. Traditionally, the industry has let these fall between the two manufacturers, essentially screwing the customer.
• Offer a ridiculously generous warranty and stand behind it. No matter what.
